What is an Ishikawa diagram used for?

• A. Fishbone diagram used to identify root causes by categorizing factors (man, method, machine, materials, measurement, environment)
• B. Gantt chart used to schedule tasks
• C. Pareto chart used to rank failures
• D. Flowchart used to document procedures

Answer: (A)

An Ishikawa diagram helps a team identify root causes of a problem by organizing potential contributing factors into major categories. The diagram looks like a fishbone, with the problem stated at the head and the main categories forming a spine with branches. In manufacturing and maintenance contexts, typical categories are man (people), method, machine, materials, measurement, and environment. By brainstorming under each category, you surface possible causes such as operator error, outdated procedures, worn parts, poor maintenance timing, low-quality inputs, or harsh operating conditions. This structured visualization moves the discussion from symptoms to underlying causes and supports choosing corrective actions that address root causes rather than just treating symptoms.

For comparison, a Gantt chart focuses on scheduling and tracking tasks over time; a Pareto chart ranks problems by how often or how severely they occur to prioritize improvements; a flowchart maps the steps of a process to show sequence and decision points. The Ishikawa diagram is distinct in its goal of organized root-cause analysis through categorized brainstorming.